Practical RIS-Aided Coded Systems: Joint Precoding and Passive Beamforming

Reconfigure intelligent surface (RIS) is considered as a promising technology for next generation wireless networks to improve spectrum efficiency or energy efficiency. This letter, for the first time, investigates a practical RIS-aided coded system. Specially, we consider a forward-error-correction (FEC) code and a linear precoder at the transmitter, while a low-complexity iterative receiver is adopted. In addition, the inter-symbol interference (ISI) channels are considered. We aim to jointly optimize the precoding and the passive beamforming of the RIS to minimize the transmission power given the bit error rate (BER). To solve this non-convex optimization problem, we utilize the alternate optimization to iteratively optimize the precoding and passive beamforming, which are respectively a convex problem and a fractional programming problem. Numerical results show that significant performance improvement can be achieved with the proposed optimization scheme.

Automated summary

Reconfigurable intelligent surface (RIS) is considered a promising technology for next-generation wireless networks to improve spectrum efficiency or energy efficiency. This letter investigates a practical RIS-aided coded system for the first time, optimizing precoding and passive beamforming to minimize transmission power given the bit error rate (BER). Utilizing alternate optimization, significant performance improvement is achieved through iterative optimization of precoding and passive beamforming.